With Mercury you can do the same things as with your normal MSN messenger.
Basic IM functions

* Talk to friends
* Change your nickname and status
* Add a display picture (also know as avatar)
* Send files through the msn server (for people with a firewall etc..) and direct
* Away messages, auto away using idle check on Windows, auto away using screensaver check on Mac OS X

MSN specific functions

* Play games, current games: Tic Tac Toe (MSN default game), Connect4 (Mess.be game)
* Watch the webcam of your friends (Mercury auto-saves these sessions on the disk and can convert them to Quicktime movies, click here for more info)
* Allow other people to watch your webcam (= video only)
* Audio and Video conference is implemented (both sending and receiving) but still a beta feature.

MSN7 specific functions

* Send and receive winks (sending custom winks doesn't work yet due to new security restrictions in MSN7.x)
* Personal messages
* Showing your current song, directly using winamp on Windows, ITunes on Mac OS X and a shell command on every OS
* Send and receive nudges
* Receive voice clips (sending is not yet supported, the audio codec is probably Windows only so I don't feel doing research on it at the moment)

Extended IM functions

* Partial UPNP support (Port forwarding), this should make the file transfers for some users faster...

* Searching in the contact list (CTRL + F)
But Mercury has some extra features that your normal messenger doesn't have, for example:

OS independent

* Support for multiple operating systems, you can run the same Mercury version on Mac OS X, FreeBSD, Linux and Windows.

Extended MSN functions

* Be online with several MSN addresses at the same time (without starting a new program for every account)
* Login with your status on 'Invisible' or any other status you want.
* Have a different MSN name in every conversation (Personal name)
* Send screen shots to your contacts
* Add more then 12 users in one conversation (MSN messenger limit)
* Special codes in your name.
* Nick scroller, change your name every 30 seconds into something complety different (allows the usage of the special codes)
* Avatar scroller, automaticly change your avatar every 5 minutes
* Background image scroller, automaticly change backgrounds every x minutes
* Send larger avatars then normal
* Override someones avatar
* Enter notes while in a conversation you might need later (date of birth, last name, phone numbers)

Plugin support

* Use and create your own plugins
* Custom games:
o Chess
o Risk
o you can also create them yourself

Improved events

* See when someone starts a conversation with you before he says something (this has been removed from MSN7, Mercury will now show when someone starts typing, this is the closest I could get to the old function)
* See when someone closes the chat conversation window.
* See who added you into a conversation with multiple people
* See when someone deletes you from their contactlist.
* See what MSN client version someone is using (or emulating, Mercury currently emulates 7.5)
* See if someone in your list is using Mercury
* See if someone in your list has a webcam (if he/she allows you to see it)
* See your fake, faked and ghost friends

* Specific triggers for each person (trigger = action after event)
* Supported actions for a trigger include sound, a popup window, a windows balloon (balloon=Windows only), shaking a window
* Support for Growl

Access to resources

* All avatars downloaded are stored on your computer in PNG format (96x96)
* All webcam streams are stored on your computer, you can convert them to a Quicktime movie if you want or watch them internally using the webcam stream player
* All personal emoticons downloaded are stored on your computer

Extended IM functions

* Text recall.
* Auto log chat conversations, always log your chats so you can read back everything that is said between you and your contacts.
* Auto login multiple accounts on startup.
* Auto away, change your status to away (or anything else) after x seconds of idle time (Windows only)
* Auto update when a new version is available (Mercury asks if you wish to update when new version is available)
* XML and text based chat logs

Extended customizing

* Customise all menu bars.
* Customise your contact list:
o Hide offline contacts
o Show emoticons in the list
o Sort contacts by group, status or both
o Show contacts by email, MSN name, alias or a combination of the above, supports multiple lines (List view)
o Change the status icons
o See the difference between contacts using Mercury, contacts having a webcam, fake friends and more
o Show display pictures in the list
* Customise your conversation area: (1710 Beta and up)
o By using HTML you can make your conversation looking the way you want it to
o By downloading views other people made, you can find the view you like the most without making it yourself

* Show contacts in the program by email, MSN name, alias or a combination of the above (General view)
* Add new status icons
* Mercury has 10 custom skins and 3 java skins
* XML based setting files.

What's New:

- Webcam / Video Conference Support: In this version of Mercury, both webcam sending and receiving are available.
- Growl Support: Mercury supports Growl (https://growl.info) event notification.
- iTunes Support: With Mercury you can control iTunes by typing commands in any chatwindow.The commands are as follows: /isong (show song details); /iplay; /inext; /iprev; /ipause. You may also display your current song in your Display Name, using these codes: %ITunesSong% (show iTunes current song); %ITunesStatus% (show iTunes status).